Ionic liquid grafted cellulose nanocrystal and preparation method thereof

A technology of ionic liquid and cellulose, which is applied in the field of ionic liquid-grafted cellulose nanocrystals and its preparation, can solve the problems that ionic liquids cannot be grafted in the form of covalent bonds, and achieve improved redispersibility and durability Improved thermal performance and easy operation

Active Publication Date: 2020-05-29
QINGDAO UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the chemical grafting process, since the sulfonate groups on the surface of cellulose nanocrystals are prone to electrostatic attraction with the positive charges of ionic liquids, ionic liquids cannot be grafted on the surface of cellulose nanocrystals in the form of covalent bonds. One problem, the present invention has adopted organic acid monomer as " bridge " between ionic liquid and cellulose nanocrystal this measure, and this method does not change the crystal form and crystallinity of cellulose nanocrystal; Improve cellulose nanocrystal crystal redispersibility in water; the Zeta potential of the modified cellulose nanocrystal suspension shows positive charge and pH responsiveness; and the heat resistance and carbon residue of the cellulose nanocrystal are significantly improved

Method used

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  • Ionic liquid grafted cellulose nanocrystal and preparation method thereof
  • Ionic liquid grafted cellulose nanocrystal and preparation method thereof
  • Ionic liquid grafted cellulose nanocrystal and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] 20 mL of 2% sulfonated cellulose nanocrystal suspension at pH=7 was added to a one-necked flask, and 5 mg of zinc acetate and 5 g of lactic acid monomer were added after ultrasonication. Place the single-necked flask in a water bath at room temperature until the temperature reaches 180°C and keep it for 10 minutes, add cold water to stop the reaction, and then centrifuge repeatedly to obtain cellulose nanocrystals modified by lactic acid monomers; disperse them into a three-necked flask filled with 8 mL of deionized water Add 5g of 1-vinyl-3-butylimidazolium tetrafluoroborate ([VBIm][BF 4 ]), ultrasonically added 50mg of azobisisobutyronitrile / methanol solution 2mL, fully stirred and reacted at 70°C for 24h, the product was washed and dried to obtain a white or light yellow solid. [VBIm][BF 4 ] The degree of substitution on the surface of the cellulose nanocrystal is 34%, and the Zeta potential of the resulting cellulose nanocrystal is 52mv.

[0047] The photo of the ...

Embodiment 2

[0049] Selected raw material type and technological process are with embodiment 1, and difference is [VBIm] [BF 4 ] is 8g, the Zeta potential value of the resulting cellulose nanocrystal is 45mv, and the ionic liquid [VBIm][BF 4 ] The degree of substitution on the surface of cellulose nanocrystals is 27%.

Embodiment 3

[0051] Selected raw material type and technological process are with embodiment 1, and difference is [VBIm] [BF 4 ] is 2g, the Zeta potential value of the resulting cellulose nanocrystal is 31mv, and the ionic liquid [VBIm][BF 4 ] The degree of substitution on the surface of cellulose nanocrystals is 17%.

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Abstract

The invention provides an ionic liquid grafted cellulose nanocrystal and a preparation method thereof. Hydroxyl on the surface of the cellulose nanocrystal and carboxyl of an organic acid monomer aresubjected to esterification reaction in a water phase; and free radical reaction is initiated between the ionic liquid and the organic acid monomer grafted on the surface of the cellulose nanocrystalby using a free radical initiation system in a water/water-soluble organic solvent blended solution or a water phase so as to initiate grafting of an alkenyl ionic liquid monomer on the surface of thecellulose nanocrystal. According to the method, the crystal form and crystallinity of the cellulose nanocrystal are not changed; the redispersibility of the cellulose nanocrystals in water is improved; the Zeta potential of the modified cellulose nanocrystalline suspension shows positive electricity, and meanwhile, the modified cellulose nanocrystalline suspension has pH responsiveness; and the heat resistance and residual carbon content of the cellulose nanocrystal are obviously improved.

Description

technical field [0001] The invention relates to a cellulose nanocrystal grafted with an ionic liquid and a preparation method thereof, belonging to the technical field of new material preparation. Background technique [0002] Cellulose nanocrystals, derived from the most abundant renewable biopolymer-cellulose, have attracted extensive attention for their high rigidity, low density, high specific surface area, and good mechanical properties. However, the nanocrystalline properties of cellulose greatly limit its applications in different fields. In order to improve certain properties of cellulose nanocrystals or endow them with other functions, functionalized monomers or polymers are grafted onto the surface of cellulose nanocrystals through various modification means. Among them, aqueous phase modification is widely favored by scientific researchers because of its environmental friendliness. [0003] Ionic liquids are organic salts that are in a molten state at room tempe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F251/02C08F226/06
CPCC08F251/02C08F226/06Y02P20/54
Inventor 张建明王丽段咏欣李文浩胡洁
Owner QINGDAO UNIV OF SCI & TECH
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